As for reviews, I thought we've covered that in this thread - most consumers don't read reviews.
I'm a little confused by something. You acknowledge that the majority of the Wii userbase is uninformed, but you think they are the types of gamers who would buy "bloctbuster" games, which typical sell only to the "hardcore" crowd?
Blockbuster games don't just sell to the hardcore crowd any more than blockbuster movies are only seen by hardcore movie goers.
The fact that the Wii Fanbase is uninformed is what makes them navigate to blockbuster titles... "Ohhh, I saw this shiny game on TV! Buy!"
I know several people discount the effects of a proper advertising campaign - but then how do you explain Professor Layton? Game came out, sold... questionably (to the point people thought the sequels wouldn't be released in the US) - then, bamn - a few months later, Phoebe is on TV doing commercials for the game and it's topping the sales charts.
But, again, this goes back to the idea of a proper advertising campaign - knowing the market you're aiming for (and should be aiming for). Metroid Prime 3 is a good example - it had the one commercial... It was probably the weakest of the "Wii would like to play" line-up... and that these just wasn't suited for the type of game Metroid is - it's not a party game or a group game - it's a solo adventure. Shooting and exploration. Not something "we" play.